Looking after Broad-fruited Cornsalad Valerianella rimosa

Ecology and Conservation Portfolio Ecology and Conservation Portfolio / BROAD-FRUITED CORNSALAD, Valerianella rimosa

At a glance Common name: Broad-fruited Cornsalad Scientific name: Valerianella rimosa Habitat types: found almost exclusively in arable habitats, specifically the margins of fields sown with winter and spring cereals Soil type: free-draining acidic shales and sands, and slightly calcareous heavy clay soils GB status: Endangered

Contents At a glance ...... 2 Species description ...... 3 Lifecycle and ecology ...... 3 Case studies: Broad-fruited Cornsalad fluctuations at Fivehead Arable Fields ...... 5 Habitat ...... 6 Soil profile ...... 6 Case studies: Discovery of a new Broad-fruited Cornsalad population in Cornwall ...... 8 Vegetation communities...... 9 Distribution ...... 10 Reasons for decline ...... 11 GB status and rarity ...... 11 Protection under the law ...... 11 Cultural connections ...... 11 Survey method ...... 12 Habitat management ...... 12 Case studies: How do herbicide applications, season and depth of cultivation affect rare cornsalads? ...... 14 The highs and lows: how Broad-fruited Cornsalad can bounce back ...... 15 Reintroduction ...... 16 Areas for futher research ...... 16 Case studies: Increasing the number of Broad-fruited Cornsalad populations in Devon ...... 17 Species Population Survey Recording Form: Arable Note that many of the sites mentioned in this Plants ...... 18 report are privately owned and not publicly Glossary...... 22 accessible without landowner permission. Case study list ...... 22 References ...... 22 Further reading ...... 23 Broad-fruited Cornsalad / Ecology and Conservation Portfolio Acknowledgements ...... 23 © Plantlife 2021. Design and graphics: lonelycottage.co.uk. Map contains Ordnance Survey data © Crown copyright and Contributors ...... 23 database right 2020. Cover photo: Cath Shellswell.

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Species description

Broad-fruited Cornsalad is a hairless, slender plant up to 30 cm tall. It is usually branched with opposite, narrow, spear-shaped stem leaves. The basal leaves form a flat cluster close to the ground. The tiny white to pink-tinged flowers have five petals and are about 2 mm in diameter and borne in clusters at the end of stems (Figure 1). Usually there are additional single flowers in the forks of the stem branches, and it is these single flowers that develop into the first seeds. Each flower produces a single seed which is nearly spherical, about 1.5 mm in diameter and has a single terminal tooth. The clusters of seeds at the ends of the stems can be quite eye-catching when large numbers of well-grown plants are present1. Most of the seed capsule is hollow.

All cornsalads are quite similar in appearance but the best way to distinguish them is by their seeds. Broad- fruited Cornsalad seeds are like small grape pips and swollen (2 mm long by 1.5 mm wide). There are small teeth (the remains of the calyx) at the top of the seed which are equal in length (Figure 2). The most similar species is Narrow-fruited Cornsalad Valerianella dentata which has much narrower seeds (0.75 mm wide), with a single tooth on top, whilst Hairy-fruited Cornsalad Valerianella eriocarpa also has narrow seeds (0.75 mm wide) with small hairs and the calyx remnant forming a ‘crown’ with six distinctive teeth (Figure 3).

Lifecycle and ecology

Broad-fruited Cornsalad is an annual herb, flowering from June to August (Figure 4). It mainly germinates in autumn with a rosette of leaves overwinter. It can also germinate after spring cultivation1, but then tends to be smaller and less-branched, and produces less seed. In experimental studies of germination, most seedlings appeared between September and December, and in a field study, plants were most abundant in plots drilled between mid-October and the end of November2. It is possible that autumn-germinating plants flower earlier in the year than spring-germinating plants and may be more productive. Seed is usually shed from July onwards3. Broad-fruited Cornsalad is probably best classified as a stress-tolerant ruderal.

Little is known about breeding systems in this species. Flowers are bisexual and it is likely both cross- and self-pollination occurs, as happens in related cornsalad species4. The flower structure suggests pollination is carried out by small insects such as hoverflies and flies.

Figure 1: Like all cornsalads, Broad-fruited Cornsalad has small whitish flowers © Cath Shellswell

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temperatures in the winter. This is typical behaviour of autumn-germinating annuals of temperate regions.

The Royal Botanic Gardens (RBG) Kew’s Millennium Seed Bank (MSB) holds germination testing data for five UK collections of Broad-fruited Cornsalad. These data suggest that plants will germinate without pre- treatment at temperatures of greater than 10°C and alternating temperatures of 25°C and 10°C, although the germination rate varies between collections from different populations. In one collection, germination was promoted by a period of cool incubation at 10°C for four weeks followed by an alternating temperature regime of 25/10°C. Separate germination peaks were observed at each temperature, with the first within two weeks of incubation at 10°C and the second two weeks Figure 2: Broad-fruited Cornsalad seeds (left) and Hairy-fruited Cornsalad seeds (right) showing the significant difference in size and into incubation at the alternating temperature regime. shape © Hannah Gibbons Variation within and between collections of the same native species is not uncommon and may be influenced by factors including environmental conditions at the It is not known how long Broad-fruited Cornsalad seeds collecting site, the time of collection, post-harvesting can remain dormant within the soil. Other cornsalad handling and storage3. Further research on dormancy species are said to have long-lived seeds (over 30 years) mechanisms of Broad-fruited Cornsalad would be and this might be the case for Broad-fruited Cornsalad. beneficial to fully understand the seed biology. The introduction of suitable management at sites where there were historical populations could encourage germination of seeds from the soil seed bank1. Habitat

Germination usually occurs immediately after seed is Broad-fruited Cornsalad is found almost exclusively shed from the parent plant and is suppressed by low in arable habitats in Britain, specifically the margins

i) ii) iii)

Figure 3: Illustrations of seeds of: i) Broad-fruited Cornsalad; ii) Hairy-fruited Cornsalad; and iii) Narrow-fruited Cornsalad. Illustrations by evansgraphic.co.uk © Plantlife

Flowering period JF M A MJ J A S O N D

Setting seed J F M A MJ J A S O N D

Germination time J F M A MJ J A S O N D

Figure 4: Flowering, germination and seed-setting periods for Broad-fruited Cornsalad

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Broad-fruited Cornsalad population fluctuations at Fivehead Arable Fields Fivehead Arable Fields is owned and managed by Somerset Wildlife Trust and is one of just three SSSIs notified for their assemblage of rare arable plants.

Crops have not been grown on the reserve since perenne was also present in many of the units following 2017-2018 when the site was entirely given over to the sowing of grass leys as a method of controlling some cornfield flowers. Fivehead Arable Fields has three of the more competitive problem plants. fields with one large field split into two management units (four The population of Broad-fruited units in total). Each year, three Broad-fruited Cornsalad fell by 48% between management units are autumn- 2010-2017 and, during the cultivated and one spring- Cornsalad appears to same period, Onion Couch cultivated, and this management grow better in areas Arrhenatherum elatius increased is rotated around the four units. by 30% in unit 3. Broad- with lower grass cover fruited Cornsalad responded The cornfield flowers at Fivehead favourably to the graminicide in Arable Fields have been 2018, increasing in all autumn- monitored using a Rapid Assessment method since cultivated fields. However, the problem grasses and 1997. This is a simplified version of Common Standards pernicious weeds have since increased between 2018- Monitoring. Usually, this survey for annual plants is 2020. The consistently largest population of Broad- undertaken every year, but there are some breaks in the fruited Cornsalad between 2010-2019 was in unit 2 data and the survey list has evolved over time to include with plants present in 80-95% of quadrats (Figure 5). more positive indicator species, as well as negative Lower levels of grasses were also recorded in this unit indicators. The purpose of this monitoring is gauge the which may explain why Broad-fruited Cornsalad was efficacy of the management and make adjustments able to grow so prolifically. as necessary. For example, in 2017, Onion Couch Arrhenatherum elatius var. bulbosum, Barren Brome Rapid Assessment monitoring will be continued to Bromus sterilis, Soft Brome Bromus effusus and Black- monitor the population sizes of positive and negative grass Alopecurus myosuroides had reached levels that indicator species. Broad-fruited Cornsalad has not been were damaging populations of positive indicator species, recorded in any spring-cultivated areas between 2017- and a spring graminicide spray was undertaken in 2018 2020, and at this site it appears very strongly associated to reduce the level of grass. Perennial Rye-grass Lolium with autumn cultivation.

100 Broad-fruited Cornsalad Black-grass 80 Onion Couch

Graminicide spray Graminicide Wild Oat 60 Bristly Oxtongue Perennial Sowthistle

present 40

20 Percentage of quadrats with species of quadrats Percentage 0 2017 2018 2019 Year

Figure 5: Percentage of quadrats with Broad-fruited Cornsalad and negative indicator species from 2017 to 2019 in unit 2

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of fields sown with winter and spring cereals. It also Texture triangle: Soil Survey of England Wales (UK) occurs rarely in disturbed sites adjacent to arable land and on former arable land until the associated perennial 10 vegetation becomes too dense. 90

20 80

Traditionally, the species is considered to favour 30 areas that are poor in nutrients, often where the crop 70 40 canopy is very sparse and where there is relatively little [%] Clay60 0-2 µm Cl 5 [%] Silt 2-60 µm competitive pressure . Surveys have found Broad- 50 50 fruited Cornsalad growing in contradictory situations; SiCl 60 in fairly open, short swards where there is enough 40 SaCl surrounding vegetation to enable the branching plants 30 70 to sprawl and in areas of denser vegetation with higher CILo SiCILo SaCILo 80 than expected soil nutrient levels. 20 90 10 SaLo SaSiLo SiLo LoSa Broad-fruited Cornsalad has been found at four non- Sa arable sites since 1987. At two locations, north of 90 80 70 60 50 40 30 20 10 Padstow in Cornwall, it has been found on wind-blown [%] Sand 60-2000 µm sand on cliff-tops next to arable land. No plants were seen here during a survey in 2018, though it is possible Figure 6: Soil triangle showing the proportions of clay, silt and sand that it might reappear here, perhaps following erosion present at the six Broad-fruited Cornsalad populations or other disturbance. In Gloucestershire, it has been recorded on quarry spoil. It may still occur at a quarry in mid-Somerset where all five British cornsalad species Soil pH and Perfoliate (Cotswold) Penny-cress Microthlaspi perfoliatum have also been recorded. Soil pH ranges from neutral 6.5 to neutral-calcareous 7.9. The clay loams in Somerset, which overlie limestone bedrock, are more calcareous than the sandy silt loams of Cornwall Soil profile and Devon which are influenced by the acid bedrock.

Broad-fruited Cornsalad occurs on free-draining acidic Soil texture shales and sands, and on heavy clay soils that may be slightly calcareous. It is also associated with light There were two distinct soil textures at the six sites calcareous soils at a handful of locations. with Broad-fruited Cornsalad populations (Figure 6). The Devon and Cornwall populations were both on In a survey of six sites, it was present on acidic shales, sandy silt loams which are characteristic of southwest possibly with the influence of more base-rich intrusions England. These are free-draining soils and retain little and deposits of wind-blown sand. Four sites were on water with a high-moderate leaching rate for soil Jurassic limestone, three on chalk, one on chalky boulder nutrients. They also warm rapidly in the spring which clay and one on acidic Tertiary sand5. may boost growth early in the season for this generally autumn-germinating plant. The The following information about Somerset site is on clay loams soil texture and nutrients is with medium to slow drainage derived from six populations The whole range and moderate to low leaching studied for this publication. One of soil conditions rate for soil nutrients. There, soil in Cornwall and another in Devon fertility is inherently medium to on free-draining soils, sands and where Broad-fruited high, but this depends on historic shales; and the third population Cornsalad grows is not management. The warming rate in Somerset which is spread is medium which may delay the across four fields on clay loams. fully known growth of plants more than soils This restricted sample does not which warm faster. encompass the entire variety of soils supporting Broad-fruited Cornsalad, and testing Proportion of bare ground soil taken from other populations is recommended to provide a greater body of evidence about growing The proportion of bare ground varied between 5-65% conditions for this species. within a radius of 0.5 m of a plant. The average amount

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i)35 ii)600 iii)250 iv) 7000

30 6000 500 200 25 5000 400 150 20 4000 300 15 3000 100 Calcium ppm Phosphate ppm Potassium ppm Potassium 200 Magnesium ppm 10 2000 50 100 5 1000

0 0 0 0

Figure 7: Major plant nutrients present in the soil at six populations of Broad-fruited Cornsalad; i) Phosphate, ii) Potassium, iii) Magnesium and iv) Calcium

of bare ground within 0.5 m of of an agricultural holding and plants was 36%, and the height fertiliser may not have been of surrounding vegetation varied Broad-fruited Cornsalad routinely applied. between 15-60 cm. This suggests is associated with that Broad-fruited Cornsalad Phosphate varied between 5 ppm may, in certain circumstances, arable habitat across (Index 0.5) to 32 ppm (Index 3.3). compete with relatively dense and England and Wales, so The average phosphate level was tall vegetation once plants are 12 ppm (approximately Index established. is subject to a range of 1.2). The population with the soil nutrient conditions highest phosphate was under Soil nutrients conventional arable management in Devon. Broad-fruited Cornsalad grows mainly on arable land across England and Wales and is thus subject to a range Potassium varied between 301 ppm (Index 3.3) at the of soil nutrient conditions (Figure 7). free-draining Cornwall site to 562 ppm (Index 4.8) at the free-draining Devon site. Average potassium was 448 ppm The Devon population of Broad-fruited Cornsalad is (Index 4.2). in a cultivated margin next to an arable field managed conventionally. There have been recent periods when Magnesium varied between 101 ppm (Index 3.0) at the the whole field has been conventionally farmed, which free-draining Cornwall site to 222 ppm (Index 4.6) at the has included the use of fertiliser and herbicide. During free-draining Devon site. The average magnesium level this period, the cultivated margins (and Broad-fruited was 152 ppm (Index 3.7). Cornsalad) were not present. Soil calcium levels ranged from 1344 ppm at the Devon The Cornwall population persists in an annually population which also had the lowest pH, to 6568 ppm cultivated field margin which has not received in one of the Somerset fields, which was at the top of any fertiliser applications for at least five years. a slope and therefore may have thinner clay loams Furthermore, the population is at the top of a slope and overlying the limestone bedrock (all of the soil calcium drainage through the free-draining sandy loam may have levels were greater than 5900 ppm in Somerset). further lowered soil nutrient levels at this location. It is notable that in separate experiments with Broad- The entire Somerset population has been fruited Cornsalad growing under different nitrogen sympathetically managed for arable plants for a long applications, the mean number of plants per 4 m2 plot period and has not received any fertiliser application was found to vary from 11.8 with no additional nitrogen, during this time. Prior to being managed for arable to 6.8 with a half-rate application and 2.1 with a full-rate plants, the fields were inconsistently managed as part application5.

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Discovery of a new Broad-fruited Cornsalad population in Cornwall In 2016, the National Trust revised the management of the farm at Pentire Head in North Cornwall in line with their strategy of farming for nature.

They began work developing 6 m wide cultivated 2018 2019 2020 margins around all the arable fields to encourage wildlife Number of plants 4 53 5 associated with this habitat. Although a few arable plant recorded during surveys had been undertaken in some of the fields in summer survey the past, none of the surveys had been comprehensive Stature of plants seen Short Tall and Short and the arable rotation meant that different fields were and branched and under cultivation or in grass leys each year. stocky stocky Timing of cultivation Spring Autumn Autumn To develop a stronger baseline, the National Trust Monthly February 1.60 2.49 3.17 commissioned Plantlife to survey the entire farm in rainfall March 5.24 2.71 1.88 2016. It was at this point that both Narrow-fruited recorded at Rock, April 2.64 1.70 1.30 Cornsalad Valerianella dentata and Broad-fruited Cornwall* Cornsalad were found, with their identity later (inches) May 1.28 0.39 0.47 confirmed by the Botanical Society of Britain and June 0.18 3.78 4.93 Ireland referee for this group of plants (Figure 8). The population was estimated to comprise 15-20 large Table 1: Differences in population number, plant stature, cultivation timing and monthly rainfall in 2018, 2019 and 2020 at Pentire Head, plants bearing many seeds. Although the species was Cornwall. *Data from https://www.wunderground.com/dashboard/pws/ reported to be present in 2017, a population count was IROCK6/graph/2020-07-31/2020-07-31/monthly. Last accessed not undertaken. 25/01/2020.

This field was cultivated in April 2018 following a failed crop that had been sown in October 2017, and the spring cultivation of the margin may have influenced the population size. In the summer of 2018, four plants were recorded at Pentire Head, but these plants were fairly small (maximum 10 cm tall) and densely branched, unlike the open, spreading plants typical of this species. Some of plants appeared to have been grazed by rabbits, which could have led to the shorter, stockier growth (Figure 9).

Figure 8: The photograph used to confirm the identification of Broad- The field was next cultivated in autumn 2018 and 53 fruited Cornsalad at Pentire Head © Mike Simmonds plants were found the following summer within the same part of the field as the original 2016 population. The plants were tall with open, spreading branches. In contrast, the autumn 2019 cultivation resulted in just five short, compact plants, recorded in summer 2020.

Table 1 highlights the differences in population number, plant stature, timing of cultivation, and monthly rainfall in 2018, 2019 and 2020. In 2018 and 2020, small numbers of plants were recorded with a stocky stature, apparently unrelated to the timing of cultivation. Also, population size and stature appear unrelated to rainfall, suggesting that there are complex and poorly understood influences on the population size of this species.

Figure 9: Rabbit grazed Broad-fruited Cornsalad ©Hannah Gibbons

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There is still much to learn about available soil nutrients and uptake by plants. It appears that Broad-fruited Cornsalad can survive in a range of conditions and that soil nutrients are not necessarily harmful. However, comparing soil nutrients present at other surviving populations across the UK would help us form a more rounded picture of the conditions that this species prefers. The lower population sizes under increased nitrogen levels might be a factor in the decline of this species as atmospheric nitrogen has increased in recent years, which could increase overall soil fertility.

Vegetation communities

Broad-fruited Cornsalad (Figure 10) is typically associated with species-rich arable plant communities supporting other rarities such as Spreading Hedge- parsley Torilis arvensis, Corn Buttercup Ranunculus arvensis and Narrow-fruited Cornsalad Valerianella dentata.

To date there has been little analysis of British plant Figure 10: Broad-fruited Cornsalad © Cath Shellswell communities containing Broad-fruited Cornsalad, which is likely to be due to the small number of extant populations. In the National Vegetation Classification6 The OV15b sub-community is typically characterised there are no plant communities where Broad-fruited by frequent Dwarf Spurge Euphorbia exigua, Venus’s- Cornsalad is a consistent feature, and this species is looking-glass, Small Toadflax and Narrow-fruited not listed once within the 18 arable plant communities Cornsalad. Shepherd’s-needle Scandix pecten-veneris can in volume 5 of British Plant Communities. As such, also be present within this sub-community. it was not recorded at all within the 583 survey samples collected and analysed to identify these 18 Pentire Head in Cornwall also supports a population communities. of Broad-fruited Cornsalad within vegetation showing affinities with OV15, more specifically OV15a, the The population at Fivehead Common Chickweed Stellaria Arable Fields SSSI, in Somerset, media – Field Bindweed is found within the NVC Convolvulus arvensis sub- community OV15 Scarlet There are no plant community. This sub-community Pimpernel Lysimachia arvensis communities where is typified by the presence of – Common Field-speedwell less habitat-specific and more Veronica persica community, Broad-fruited Cornsalad competitive arable plants. showing closest affinities with is a consistent feature Grasses such as Wild Oat Avena the OV15b Venus’s-looking- fatua, Black-grass Alopecurus glass Legousia hybrida – Small myosuroides and Creeping ToadflaxChaenorhinum minus Bent Agrostis stolonifera are sub-community. This community is characterised by the often common. OV15a tends to be found where soil dominance of small ephemeral species such as Scarlet nutrient levels are higher (relative to other OV15 sub- Pimpernel, Common Field-speedwell and Knotgrass communities), often due to fertilisation, albeit historical. Polygonum aviculare agg. In late summer, Sharp-leaved Fluellen Kickxia elatine and Round-leaved Fluellen At Lower Bowden in South Devon, the plant community Kickxia spuria often become noticeable within this supporting Broad-fruited Cornsalad is quite different, plant community, with their downy shoots carpeting showing affinities with OV4 Corn MarigoldGlebionis the ground. OV15 is typically characteristic of cereal segetum – Corn Spurrey Spergula arvensis and, more crops on base-rich soils of the south-east of Britain. At specifically, OV4b the Creeping ButtercupRanunculus Fivehead Arable Fields SSSI this vegetation community repens – Prickly Sowthistle Sonchus asper sub- occurs on very heavy clay over Jurassic limestone and is community. OV4 occurs widely throughout Britain on botanically diverse. light, fertile, acidic soils, although it is most frequent

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on less intensive arable land in the west. The most KEY distinctive feature of this community is the constancy of 2000+ Corn Spurrey and Corn Marigold, the latter often being 1987–1999 abundant and very conspicuous with its large yellow flower heads. Knotgrass and Annual Meadow-grassPoa 1900–1986 annua are also constant species with frequent Common Couch Elymus repens, Shepherd’s-purse Capsella bursa- pastoris and Common Chickweed. At Lower Bowden, Broad-fruited Cornsalad was noticeable in that it was more vigorous and abundant where the vegetation was opener, and Corn Marigold was sparser.

Below are vegetation descriptions of three additional sites that support Broad-fruited Cornsalad. • Near Burford in Oxfordshire, it occurs in large quantities in at least three fields on heavy clay soils over Cotswold limestone. Associated species include Shepherd’s-needle, Narrow-fruited Cornsalad, Venus’s-looking-glass, Night-flowering CatchflySilene noctiflora and Blue Pimpernel Lysimachia foemina. • In mid-Hampshire, large numbers occur in two field margins with Narrow-fruited Cornsalad, Rough Poppy Roemeria hispida, Prickly Poppy Roemeria argemone and Rough Mallow Malva setigera. • It is known from a single field near the coast of the Gower Peninsula, where it occurs in a species-rich community including Small-flowered CatchflySilene gallica and Corn Marigold.

Figure 11: Broad-fruited Cornsalad distribution across Britain and Ireland. The data used to create this map has been provided under Distribution licence from the Botanical Society of Britain and Ireland (BSBI) and accessed from the Society’s online database. This species has been present in Britain since the Iron Age and is therefore classed as an archaeophyte (a plant naturalised in Britain before 1500AD). Broad-fruited have been a serious decline of this species, although Cornsalad was previously much more widespread, with a as with many annuals, caution must be observed in the scattering of records from southern England as far north interpretation of these figures, as this is a species with as central Scotland, although it has never been abundant a history of erratic appearance. A review of its status in (Figure 11). 19997 concluded that there were only four extant sites, but more recent examination of records from between In mainland Britain, most sites are located south of 2000-2020 indicates that there are just fewer than 20 a line between the Wash and Severn Estuary with a populations remaining. Further clarity should be added concentration of sites in south-west England and a with the publication of the next UK Plant Atlas. single site in Wales on the Gower Peninsula. In the New Atlas of the British Flora6, Broad-fruited Cornsalad In Ireland, there are a handful of populations in Co. has a high negative change index of –2.55. The total Wexford and one in Co. Limerick. number of 10 km squares (hectads) from which it was recorded before 1970 was 149, but it was only known Beyond the British Isles, the species occurs in southern- from 38 hectads between 1950 and 1970. Numbers central Europe, and is threatened in Germany, the of records fell to 14 hectads between 1970 and 1986, Netherlands and Switzerland. and it has been recorded from 14 hectads between 1987 and 2006. Although a few new sites have been Some of the apparent rarity of this species in the past found in recent years (one in Norfolk and another at a may have been due to confusion with the closely related coastal location in Cornwall), local extinctions continue Narrow-fruited Cornsalad Valerianella dentata, from with changes in land management, such as conversion which it is only reliably distinguishable by the shape of arable land to pasture. There appears, therefore, to of the seed. The diagnostic features of the various

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Cornsalad species are now better understood, but even though dispersal by wind or water might be assisted by so, small populations can be easily missed or confused the large and mostly hollow seed capsule. with related species. Historical records of this species suggest that it was never common in the UK. For example, in Cornwall, Reasons for decline a stronghold for this species, there are 48 records at different locations between Broad-fruited Cornsalad is 1835 and 2016. This species especially vulnerable to changes Broad-fruited was recorded at 13 locations in land management and between 1835-1900, 27 locations particularly to several common Cornsalad is especially between 1901-1930, one location practices associated with vulnerable to changes between 1931-1999, and at seven intensive farming. The widespread locations between 2000-2016. use of broad-spectrum herbicides in land management Before 2017, there are only five is likely to have inflicted the records of this species occurring greatest impact on Broad-fruited at the same location in different Cornsalad populations and it is years, though the variation also likely to have been affected (though perhaps to a in records may be due to under-recording or lack of lesser extent) by the development of competitive cereal monitoring. crop varieties combined with an increase in nitrogen application, so that the species is quickly outcompeted by closing the cereal sward, preventing light from GB status and rarity reaching the seedlings. Broad-fruited Cornsalad grows poorly where surrounding vegetation is thick and tall. Endangered.

Winter-sown cereal crops tend to be more intensively managed than spring-sown crops, typically with far Protection under the law higher nitrogen and herbicide application rates, aimed at improving the crop yield. As Broad-fruited Cornsalad Broad-fruited Cornsalad is included as a species of tends to prefer autumn cultivation, this management is principal importance for the purpose of conserving likely to negatively affect this species. biodiversity under Section 41 (England) of the Natural Environment and Rural Communities Act 2006. A more recent threat is the loss of arable habitat to grassland and/or vegetable production. As small-scale arable farms become less profitable in Britain, the fields Cultural connections where Broad-fruited Cornsalad is present are likely to be turned over to different management. The first parts The greatest use for Valerianella is as a salad crop using of fields to be withdrawn from cultivation are usually the species Lamb’s Lettuce or Common Cornsalad the less productive field margins which are also the last Valerianella locusta. Seeds of the plant have been found refugia of many rare arable plants. These are converted at Neolithic and Bronze Age sites. It was first taken into to grassland, sometimes as part of agri-environment cultivation in Western Europe during the seventeenth schemes designed to benefit farmland wildlife. It is century where is was especially valued as a winter salad essential that the management of field margins under crop. Healing properties attributed to cornsalad include agri-environment schemes is planned using the available regulation of bowels, preventing infection, cleansing of information on distribution of uncommon arable plants. blood and preventing spring fatigue8.

Non-arable sites are at risk from successional processes. These involve the development of closed grassland Survey method communities and scrub. Coastal sites may be vulnerable to cliff erosion. Individual plants should be counted in smaller populations of fewer than 100 individuals. Larger The seeds of Broad-fruited Cornsalad are medium-sized, populations should be estimated, or an alternative lacking projections that would help in dispersal, and they strategy would be to map the extent of the distribution. would have been easily removed from cereal seed even Other factors could also be recorded, such as the with the most primitive seed-cleaning technology. They method and depth of cultivation, the application and have no obvious aids to transport by animals or wind, type of any fertiliser or herbicide, soil texture and

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nutrient levels if a soil test was undertaken. As Broad- early December) or spring (between February and early fruited Cornsalad grows within a community of plants, April), and then little disturbance until the following it is useful to record associated species. An example of a autumn by which time the plants will have set seed. recording form is contained within the appendix. Autumn cultivation is more suitable for heavier clays where there may be difficulties cultivating in the spring if the soil becomes saturated overwinter. Habitat management Broad-fruited Cornsalad readily germinates from seed, Ideal management, on arable land, requires annual and needs soil disturbance, such as ploughing, to bring cultivation preferably in autumn (between October and buried seed to the soil surface and trigger germination.

Survey methodologies for different population sizes There are three recommended methods for assessing population size depending on the general abundance of the plant being surveyed.

These methods have all been used to estimate Broad-fruited Cornsalad population sizes. It is important to ensure that the survey is carried out at the optimal time of year, when the seeds have started to mature, but are not so mature that they have fallen from the plant.

Counting: If there are few plants or if they are Scaling-up using transects: This is a method for 1 scattered and easy to count, it is recommended 3 populations which are scattered over a large that a simple count is made. This is likely to be most area. It requires a small to large team of people to suitable if walking around the margin of a field. walk over the area where the plants are present to As the species is quite branched, it can be difficult estimate population size. to identify individuals growing in close proximity. Giving a plant a wiggle can help identify if more In order to estimate the population, first examine than one plant is present or if a single plant is a few plants to get a feel for the size and shape branched. that an individual plant occupies and covers. This enables all members of the survey team to get Scaling-up using quadrat data: If plants are an eye for the stem branches, fruits and spread 2 scattered evenly throughout the vegetation of plants which can be very different sizes. It is it might be worth counting the number of plants especially useful to do this when Broad-fruited within quadrats, taking an average and then scaling Cornsalad is growing with other members of the up. The size of the quadrat used will depend on the same family, such as Narrow-fruited Cornsalad frequency of the target plant. This methodology is Valerianella dentata. In addition, it gives a rough probably best suited when Broad-fruited Cornsalad visual baseline of expectations when counting. is not just restricted to the margin but found in a wider area, such as a wide cultivated margin, Each person should then walk in a straight line at and if only one or a few people are surveying the an agreed distance apart from one side of the area population. to the other trying to keep pace with one another. As a guide, stationing surveyors 3-4 m apart allows For ease, the quadrat size should be no more than for a comfortable field of vision, whilst attempting 2x2 m. For example, ten 1x1 m quadrats were to avoid double counting. Each surveyor needs to surveyed within the 6 m wide cultivated margin keep a record of the number of plants of the target where Broad-fruited Cornsalad seemed evenly species that they see within their strip of the field. distributed. An average of 3 plants were found Once the population has been walked, all individual per m2. The plants occurred within a 20 m length tallies are totalled to give a population count for of the margin, therefore within an area of 120 m2. the area covered. This process can be repeated As such, the estimated population for the site was in another part of the population area (if not all 3x120=360 plants. covered in one go) or scaled up.

Box 1: Survey methodologies for Broad-fruited Cornsalad populations

12 Ecology and Conservation Portfolio / BROAD-FRUITED CORNSALAD, Valerianella rimosa

In cultivation depth trials, within a crop, the crop should ploughing was found to increase Broad-fruited Cornsalad be harvested after the plant has densities of Broad-fruited readily germinates from set seed, usually from late July Cornsalad compared to minimum onwards. tillage. It will grow within a crop, seed such an autumn- or spring-sown In non-arable habitats, open cereal, oil-seed rape or field ground should be restored and beans, or within an uncropped cultivated area or plot maintained annually through rotavation in autumn or (Figure 12). spring if natural processes do not facilitate open ground.

It is susceptible to broad-spectrum herbicides and As Broad-fruited Cornsalad seed is believed to be their use will reduce population sizes. However, if at least moderately long-lived in the soil seed bank, required, treatment of problematic weed species could there is a good chance that reinstatement of suitable be undertaken by using targeted herbicides. Fertiliser management could provide enough germination and can encourage problem weeds. It is not usually applied establishment niches where populations have been to uncropped areas for arable plants and is limited recorded in the recent past. If the species has not on cereal headlands and wildlife cover crops9,10. The been recorded recently, or has failed to return under a number of Broad-fruited Cornsalad plants surviving favourable management regime, reintroduction is likely under a winter wheat canopy with a normal farm level of to be required. nitrogen application was less than 20% of the numbers surviving where no nitrogen had been applied5. Reintroduction Using a reduced seed-sowing rate and/or a crop variety that has fewer tillers on conservation headlands, Sowing seed in autumn mimics natural seed dispersal alongside a reduction in the application of nitrogen, and provides an opportunity for autumn germination will also benefit Broad-fruited Cornsalad, as it is a and the establishment of larger and more productive poor competitor. If Broad-fruited Cornsalad is growing plants (Table 2). Seed which does not germinate in

Figure 12: Broad-fruited Cornsalad will grow within a crop or in an uncultivated area © Cath Shellswell

13 Ecology and Conservation Portfolio / BROAD-FRUITED CORNSALAD, Valerianella rimosa

How do herbicide applications, season and depth of cultivation affect rare cornsalads? A series of trials undertaken at Fivehead Arable Fields SSSI investigated the effect of season and depth of cultivation and herbicide application on the arable flora, including Narrow- fruited Cornsalad Valerianella dentata and Broad-fruited Cornsalad.

Unsprayed Graminicide Graminicide + BL Glyphosate 150

2 100

50 Individuals m

0 Disc Harrow Plough Disc Harrow Plough (‘Scratch’) (‘Middle’) (‘Deep’) (‘Scratch’) (‘Middle’) (‘Deep’)

Spring Autumn

Figure 13: Densities of cornsalad plants within the experimental plots at Fivehead Arable Fields SSSI under: i) different timing of cultivation (spring or autumn), ii) depth of cultivation (discing which disturbs the soil surface and is used for initial seed bed preparation; power harrowing which is a non- inversion method of cultivation creating a tilth to a depth of 10 cm; and ploughing which is inversion tillage, turning over the soil to a depth of 30 cm with a subsequent pass over with a power harrow to create a fine seed bed), and iii) herbicide treatment (untreated; treated with graminicide; treated with graminicide and broad-leaved herbicide; treated with Glyphosate, which kills both grasses and broad-leaved weeds.)

These two species are impossible to distinguish before soil seed bank, with more cornsalad seed in combined they produce seeds and the surveyors did not distinguish graminicide and herbicide plots that had either been between the species to prevent count errors. harrowed or ploughed. Lower numbers of cornsalad seed were found in the soil of disced plots that had just In this experiment, cornsalads had an almost exclusive received either graminicide or combined herbicide. preference for autumn cultivation (Figure 13). Ploughing also increased densities of cornsalads compared with The graminicide application had a potentially controlling discing and harrowing. This was irrespective of soil seed effect on more competitive problem species. At bank densities which were high across all experimental Fivehead Arable Fields SSSI, cultivation in autumn was plots. There was also a combined effect of herbicide associated with the undesirable grasses Creeping Bent treatment and cultivation depth, with densities of Agrostis stolonifera, Black-grass Alopecurus myosuroides, cornsalads twice or three times higher on graminicide- Onion Couch Arrhenatherum elatius var. bulbosum, Wild sprayed, autumn-ploughed plots than on unsprayed Oat Avena fatua and Smooth Brome Bromus racemosus. autumn-disced or harrowed plots. This alludes to the In addition, several undesirable weed species were impact of autumn-germinating grasses on cornsalad associated with the less intensive cultivation methods populations. of discing and harrowing. This included Smooth Brome, Italian Rye-grass Lolium multiflorum and Bristly At the outset of the trials, the soil seed bank was Oxtongue Helminthotheca echioides. The benefit to found to be unevenly distributed across the herbicide cornsalads of ploughing and graminicide application treatment plots. There were fewer cornsalad seeds in in the autumn shows that this management could the plots with the combined graminicide and selective boost populations of Broad-fruited Cornsalad whilst broadleaved herbicide application than in the plots that simultaneously reducing the populations of undesirable received just glyphosate. However, depth of cultivation species. was found to be a more significant factor influencing the

14 Ecology and Conservation Portfolio / BROAD-FRUITED CORNSALAD, Valerianella rimosa

The highs and lows: how Broad-fruited Cornsalad can bounce back Broad-fruited Cornsalad had been recorded at Lower Bowden Farm, South Devon in 1997, 1999 and 2005.

Figure 14: Cultivated margin in South Devon containing tens of thousands of Broad-fruited Cornsalad plants © Hannah Gibbons

It was surveyed thoroughly in 2018, but the species The wet weather of autumn and winter 2019 prevented was not found, although a single Narrow-fruited the field from being cultivated again until spring 2020, Cornsalad plant was seen within a gateway. The field and in summer 2020 the cultivated margin supported had been sown with a winter cereal crop and managed approximately 55 plants, significantly fewer than 2019. conventionally with herbicide. In autumn/winter 2018, The cultivation timing might provide some reason the field was cultivated as normal, for the lower population size in but a 2.5 m uncropped cultivated 2020, though there may also be margin was put in around the other variables involved. It was perimeter of the field. A survey in Areas of dense Corn very clear in 2020 that areas of the summer of 2019 revealed tens Marigold had fewer dense Corn Marigold supported of thousands of Broad-fruited few or no Broad-fruited Cornsalad plants creating a mat of Broad-fruited Cornsalad Cornsalad plants. This suggests growth amongst Narrow-fruited plants, suggesting it that Broad-fruited Cornsalad Cornsalad Valerianella dentata, may be disadvantaged when Common Poppy Papaver rhoeas may be disadvantaged the growth of Corn Marigold is and Corn Marigold Glebionis by its growth favoured. segetum (Figure 14).

15 Ecology and Conservation Portfolio / BROAD-FRUITED CORNSALAD, Valerianella rimosa

Activity Timing (month) Autumn cultivation and sowing Prepare the seed bed to create a fine tilth e.g. light cultivation September-October. or disking. Mark out the corners of the plot(s). September-October. Hand-sow seed (use a combination of seed with lime-free September-October. silver sand) at a rate of approximately 100 seeds per m2 (see Broadcast Sowing Method in Further reading). If conditions allow, roll the reintroduction plot(s) to press the September-October. seeds onto the soil surface. This creates the right conditions for germination. Survey and ongoing management Adult/flowering plant survey. June-July. Continued autumn cultivation of the reintroduction site. September-October and ongoing if the reintroduction is successful. Annual adult/flowering plant survey. June-July and ongoing to monitor the population.

Table 2: Recommended Broad-fruited Cornsalad reintroduction plan autumn may persist in the soil and germinate in spring, just one seed per capsule and two empty compartments when further sowing could also be undertaken if seeds (Figure 15). It is unknown why the seed capsule has are collected and stored in suitable conditions (see developed in this manner, and all cornsalads seem to Storing Wild Flower Seed in Further reading). Seed should have sterile locules. be sown onto bare, recently cultivated ground. 1 g of dried Broad-fruited Cornsalad seed contains The recommended sowing rate for cornfield annuals approximately 814 individual seeds3. like Broad-fruited Cornsalad is 100 seeds per m2 11. The germination behaviour of Broad-fruited Cornsalad appears to be variable, making it hard to predict Areas for further research germination and establishment success. Whilst high levels of germination are possible, to establish a large, Seed longevity and dormancy healthy population it may be prudent to sow at the recommended rate or higher where the supply of seed Given the high conservation value of Broad-fruited permits. Although each seed capsule is swollen and looks Cornsalad and the importance of the soil seed bank like it might contain more than one seed, actually there is in the recovery and persistence of annual plant populations, it would be useful to conduct some longevity or seed aging experiments on this species3. Similarly, a study to elucidate the dormancy behaviour of the species could be particularly useful to improving understanding and therefore conservation efforts.

Genetic diversity

No studies on genetic diversity within this species have been carried out. Such a study would be desirable to elucidate relationships between populations, especially as there are so few populations surviving and they are very fragmented across England and Wales.

Figure 15: Broad-fruited Cornsalad seed cross-section showing the full compartment containing the seed at the top and two empty compartments. © RBG Kew

16 Ecology and Conservation Portfolio / BROAD-FRUITED CORNSALAD, Valerianella rimosa

Increasing the number of Broad-fruited Cornsalad populations in Devon Two Broad-fruited Cornsalad reintroductions were carried out in South Devon during November 2019 and February 2020 (Figure 16).

The first site, Ash Tree Farm, 2,500 seeds were sown onto two was sown by hand with 2,500 narrow strips within two existing Broad-fruited Cornsalad This site is very cultivated margins. The margins seeds in November 2019 at an close to an exisiting had been walked in summer approximate rate of 100 seeds 2019 and the openest parts of per m2. This site is very close population of Broad- the margins were chosen for the to an existing population of fruited Cornsalad, reintroduction. Five plants were Broad-fruited Cornsalad and was found (one in the first plot and cultivated in autumn specifically so was cultivated for four in the second plot) during for the purpose of reintroduction. reintroduction a survey in summer 2020. The In the summer of 2020, the single plant was found to be short reintroduction plot was searched and densely branched, yet the and a well-branched single Broad-fruited Cornsalad four plants in the second margin were tall and openly plant was found, bearing about 40 seeds. branched. There were no obvious differences in the growing conditions between the two plots to cause the The second site, at Lincombe Farm, was not ploughed different growth statures. until February 2020 as the ground was too wet for heavy machinery. Broad-fruited Cornsalad seed was The long-term success of these reintroductions is as yet sown into two separate fields on the farm. The seeds unknown, but if the populations become established were sown by hand at a rate of approximately 100 they could double the known number of existing Broad- seeds per m2 a few days after the fields were cultivated. fruited Cornsalad sites in Devon.

Figure 16: Cultivated margin at a reintroduction site in South Devon ©Hannah Gibbons

17 Species Population Survey Recording Form: Arable Plants

Species: Survey Date:

Site/SSSI/Farm Name: Field/Unit Name:

Site Code: Site Designation: SSSI Unit/CWS Reference/RNR Number:

Recorders: Central Site Grid Reference:

Population Extent: Please record presence in 100 m (six-figure Growth Stage Counted: () grid reference) or 10 m (eight-figure grid reference) cells. Seedlings Grid letters Easting Northing First year rosettes Vegetative growth Flowering Fruiting Female Male Combination: Growth Type Counted: () Individual Clump/patch Mat Combination:

Population size: () Estimated area of cover: e.g. Site Description: e.g. wheel ruts, road verge, centre of ride, 0 (null) approx 10 x 2 m strip bank, sand/chalk pit/quarry, arable margin, etc. 1-10 11-100 101-300 301-500 501-1000 Density description: e.g. dense 1001-3000 cover, patchy, widely scattered 3001-10000 >10000 Actual number if counted

Management: detail: () High Mod Low None Grazing

Shading

Disturbance

Sward height (cm) <10 11-30 31-100 >100 Habitat type and condition: broad habitat, Threats or reason for the null record: () Aquatic plants only: () crop, soil type, NVC, flooding etc. Afforestation Water-body margin grazed

Agricultural improvement Water-body recently cleared Burning Water-body margin affected by drainage Is there an agri-environment scheme Lack of management Soil nutrients: option? (i.e. wild bird mix, wildflower margin, cultivated area?) Invasive species Soil test taken? Yes No

Mineral extraction pH

Is the species growing within a crop? Overgrazing Phosphorus (mg/l or index) Yes No Pollution / eutrophication Potassium (mg/l or index) What is the type of crop? Recreation Magnesium (mg/l or index) None Barley Species transient Clay content (%) Wheat Potato Under-grazing Silt content (%) Roots (i.e. beet, Urban/road development Sand content parsnips, carrots). (%) Please state: Brassicas (i.e. Other: Textural class cabbage, sprouts, i.e. clay loam radish). Please state: Other. Please state: Other:

Reproduction potential: Are the Type of cultivation/disturbance? plants in seed? Are there any None Min till (0-4 young plants? cm/0-1.5 in) Is the site suitable for germination Plough Deep plough of seeds? Provide a percentage (4-8 cm/1.5-3 in) (8 cm+/3 in+) cover of bare ground. Other – state depth of disturbance (i.e Describe the vegetation around disturbance by vehicle movements) and among the plants: Month and year of last cultivation/ Month Are there any aggressive species disturbance Year suppressing the plants? e.g. Type of herbicide? bracken, bramble, coarse grasses None Graminicide Are the plants being shaded out by trees or shrubs? e.g. conifers, Broad-leaved Graminicide bramble, hawthorn thickets and broad- leaved Is there any disturbance/activities Month and year of herbicide application Month which are affecting the plants in a good or bad way? e.g. horse riding, Year motor-bikes, dog walking, tree- Type of fertiliser? felling None Organic Please list any other nationally Inorganic Other? rare species present Month and year of fertiliser application Month

Year Percentage of bare ground within 5 1 x 1 m quadrats centred on plants of the target species Quadrat 1 Quadrat 2 Quadrat 3 Quadrat 4 Quadrat 5

Height of vegetation within 5 1x1m quadrats centres on plants of the target species Quadrat 1 Quadrat 2 Quadrat 3 Quadrat 4 Quadrat 5 NVC and associated species within a 1 m quadrat DOMIN cover scale Method for recording associated species: <4% with few individuals 1 • Centre the 1x1 m quadrat over an individual of the target species. Try and <4% with several individuals 2 do five quadrats within the same area/field/habitat with individuals at the <4% with many individuals 3 centre if the population is large enough. If fewer than 5 individuals just do the number of quadrats with an individual at the centre according to 4-10% 4 population size. 11-25% 5 • The quadrats should not overlap. 26-33% 6 • Record the grid reference of the quadrat to 10 figures, percentage 34-50% 7 bare ground and estimate the height above ground with the densest 51-75% 8 vegetation in centimetres (vegetation height). • Record all species within the 1 m quadrat. 76-90% 9 • Record the abundance of all species including the target species using the 91-100% 10 DOMIN scale. Physical Attributes • Record occurrences of the species from different habitat types on Altitude separate forms. Slope Other: Quadrat 1 2 3 4 5 Grid reference Bare ground (% cover) Vegetation height (cm) Crop (% cover) Cover using DOMIN Common name Scientific name 1 2 3 4 5

Cover using DOMIN Common name Scientific name 1 2 3 4 5 Ecology and Conservation Portfolio / BROAD-FRUITED CORNSALAD, Valerianella rimosa

Glossary References

Locule – A small compartment or chamber, 1. Wilson, P. and King, M. (2003) Arable Plants – a field as within a seed capsule or a pollen guide. Princeton University Press WildGuides series. containing cavity within an anther. Minimum tillage – A soil cultivation system with the 2. Wilson P.J. (1990) The Ecology and Conservation of (‘min-till’) goal of minimum soil manipulation Rare Arable Weed Species and Communities. PhD necessary for successful crop Thesis, Southampton. production. Rotavation – The process of breaking up the 3. Chapman, T., Pocock, S. and Davies, R. (2018) surface of the earth, or an area of Propagation protocols for ten threatened cornfield ground using a rotavator. annuals. http://brahmsonline.kew.org/Content/ Tiller – In grasses, a lateral stem produced Projects/msbp/resources/Training/Colour_in_the_ from near the base of the stem. margins_Report.pdf. Last accessed 03/12/2020.

4. Muminovic, J., Melchinger, E. and Lübberstedt, Case studies T. (2018) Genetic diversity within lamb’s lettuce (Valerianella locusta L.) and across related species • Broad-fruited Cornsalad fluctuations at determined by AFLP markers. Plant Breeding, 123; Fivehead Arable Fields by Alison Mitchell 460-466. (Plantlife) 5. Wilson P.J. (1999) The effect of nitrogen on • Discovery of a new Broad-fruited Cornsalad population populations of rare arable plants in Britain. Aspects in Cornwall by Hannah Gibbons (RSPB) of Applied Biology, 54, 93-100. • How do herbicide applications, season and depth of cultivation affect rare cornsalads? by Cath Shellswell 6. Rodwell, J.S. (Ed.) (2000) National Vegetation (Plantlife) Classification: Volume 5 Maritime communities and The research summarised in this portfolio was part vegetation of open habitats. Cambridge University of the Defra funded project BD5204 undertaken by Press. the UK Centre for Ecology and Hydrology (UKCEH), 7. Wigginton, M. (Ed.) (1999). British Red Data Books: Plantlife and the Wildlife Farming Company. This 1, Vascular Plants. JNCC, Peterborough.. project was additionally supported by research programme NE/N018125/1 LTS-M ASSIST – 8. Storl, D. (2016) A Curious History of Vegetables: Achieving Sustainable Agricultural Systems, Aphrodisiacal and Healing Properties, Folk Tales, funded by NERC and BBSRC. Assistance and advice Garden Tips, and Recipes Lamb’s Lettuce (Valerianella throughout the project were provided by Emily Swan locusta, Valerianella olitoria) https://publicism. and Mike Green from Natural England, and Somerset info/gardening/curious/15.html. Last accessed Wildlife Trust allowed Fivehead Arable Fields SSSI to 25/01/2020. be used as a study site. 9. Wagner, M., Redhead, J.W., Nowakowski, M., Shellswell, C.H., Bullock, J.M. and Pywell, R.F. (2013) Effects of cultivation and herbicide application regimes on the plant species composition of uncropped arable margins. Aspects of Applied Biology, 118; 127-136.

10. Wagner, M., Bullock, J.M., Hulmes, L., Hulmes, S., and • The highs and lows: how Broad-fruited Cornsalad can Pywell, R.F. (2017) Cereal density and N-fertiliser bounce back by Hannah Gibbons (RSPB) effects on the flora and biodiversity value of arable • Increasing the number of Broad-fruited Cornsalad headlands. Biodiversity and conservation, 26; 85-102. populations in Devon by Hannah Gibbons (RSPB) 11. Lang, M., Prestele, J., Fischer, C., Kollmann, J. and Albrecht, H. (2016) Reintroduction of rare arable plants by seed transfer. What are the optimal sowing rates? Ecology and Evolution, 6; 5506–5516.

22 Ecology and Conservation Portfolio / BROAD-FRUITED CORNSALAD, Valerianella rimosa

Further reading Plantlife (2019) Surveying for Arable Plants. https:// www.plantlife.org.uk/uk/discover-wild-plants- Back from the Brink (2019) Broadcast Sowing nature/habitats/arable-farmland/surveying-arable- Method. https://naturebftb.co.uk/wp-content/ plants uploads/2019/09/Broadcast-sowing-method.pdf Preston, C.D., Pearman, D.A. and Dines, T.D. (2002) New Back from the Brink (2019) Storing Wild Flower Atlas of the British & Irish Flora. University Press, Seed. https://naturebftb.co.uk/wp-content/ Oxford. uploads/2019/09/Storing-seed.pdf Salisbury, E. (1964) Weeds and Aliens. 2nd Edition. Plantlife (2019) Important Arable Plant Areas. https:// Collins. www.plantlife.org.uk/uk/discover-wild-plants- nature/habitats/arable-farmland/important-arable- Stewart, A., Pearman, D.A. and Preston, C.D. (1994) plant-areas Scarce plants in Britain. JNCC. Plantlife (2019) Land Management for Arable Plants. Wilson PJ (2004). Important Arable Plant Areas: A https://www.plantlife.org.uk/uk/discover-wild- Review of the Status of Nationally Rare Vascular plants-nature/habitats/arable-farmland/land- Plant Species Identified by the Draft IAPA Criteria. management-for-arable-plants-agri-environment- Plantlife, Salisbury. schemes

Acknowledgements

Thank you to Ted Chapman (Kew) and Phil Wilson (BSBI Valerianella referee and independent ecologist) for comments on the text, and John Rees for his help editing the text. Also, thank you to Mike Simmonds and RBG Kew for allowing us to use their photos.

A special thanks to all of the farmers, land managers and farm advisers who look Broad-fruited Cornsalad. This plant would not survive without your support and care.

Contributors

Back from the Brink was made possible thanks to a generous contribution from the National Lottery Heritage Fund

Citation

Shellswell, C.H., Gibbons, H., Mitchell, A., Moyse, R. and Waller, M (Eds.) (2021) Looking after Broad-fruited Cornsalad Valerianella rimosa: Ecology and Conservation Portfolio. Plantlife, Salisbury.

23 Ecology and Conservation Portfolio / Broad-fruited Cornsalad, Valerianella rimosa

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